Explosion-preventing device



R. T. F. DODDS EXPLOSION PREVENTING DEVICE Filed March 27 1922 INVENTORPatented July 8, 1924.

ROWAN '1. IE. DODDS, OF STRATFORD, ONTARIO, CANADA.

EXPLOSION -PREVENTI1\TG DEVICE.

' Application filed March 27, 1922.

To all whom it may concern:

Be it known that I, ROWAN T. F. Donos, a citizen of the United States,residing at Stratford, Province of Ontario, Dominion of Canada, haveinvented a new and useful Improvement in Explosion-Preventing Devices,of which the following is a full, clear, and exact description.

The present invention relates broadly to humidifying apparatus ordevices of this nature for use in connection with working areascontaining dangerous combustible mixtures.

The annual loss of life and property'resulting from explosions in grainelevators, grain bins, flour and feed mills, separators and the like,has stimulated considerable activity in connection with means forpreventing such explosions. These explosions have universally beenattributed to the existence in the working areas of dust or powderliberated from the material being handled, this dust or powder being insuch proportions that an explosive mixture. is produced. The actualexplosion of such mixtures may be caused by any one of a large number ofimproper conditions. Heretofore efiorts to prevent such explosions havebeen directed more particularly toward the elimination either of thedust or powder from the working area, or the elimination of the meansresponsible for the igniting or setting off of the mixture. Theseefforts have not overcome the danger inherent in industries where theseconditions exist, and the present invention is directed, not toward theelimination either of the explosive material in the atmosphere, or ofthe means which bring about the explosion, but toward means forpreventing an atmospheric condition capable of supporting the combustionor explosion of such mixtures.

By a series of experiments and investigations conducted under differentconditions and extending over a considerable period of time, I havefound that the dust or powder present in such areas possessesdeliquescent properties and therefore, when it is present in sufficientquantities in a limited supply of air, will absorb all of the availablemoisture therefrom and thereby produce an unstable atmospheric conditionwhich is easly ignited or exploded. As long as the air within theworking area contains a predetermined minimum of water vapor, ormoisture, a stable atmospheric condition is maintained, but

Serial No. 547,276.

the elimination of such vapor produces an objectionable unstablerelation between the remaining constituents of the air. The presentinvention has for its object the prevention of explosions by maintainingat all times a predetermined minimum of water vapor in the working areawhereby stable conditions exist.

The present invention embodies certain features of constructiondisclosed in my United States Patent No. 1,42%,879 of November 7, 1922,and constitutes a continuation in part thereof. A preferred means foraccomplishing the objects of this invention is illustrated in theaccompanying drawings, in which:

Figure 1 is a vertical sectional view through a grain bin constructed inaccordance with the present invention;

Figure 2 is a detail view, on an enlarged scale, of the constructionillustrated in Figure 1, and

Figure 3 is a detail view of the protective screening for theventilators.

Referring more particularly to the drawings, there is illustrated aportion of a grain bin or elevator having suitable walls 2 forming anenclosed working area 3 adapted to be filled with grain or similarmaterial 4. During the filling of such bins or elevators with grain orsimilar material, there is liberated a considerable quantity of dust.This dust is of such nature that it floats in the air and forms a dustladen condition. Due to the deliquescent properties of the dust, themoisture vapor within the working area is rapidly absorbed, and anunstable atmospheric condition results. In order to prevent the watervapor content within such working areas from falling below the watervapor content of the atmosphere surrounding the working area, I pro;vide at suitable points in any or all of the walls 2 a plurality ofangular ventilators 5 having intersecting passages 6 and 7. The passages6 communicate with the outside atmosphere, while the passages 7coimnunicate with the working area. 'Due to the shape of these passagesthe tendency of the grain to flow outwardly therethrough is largelyovercome. In order to prevent birds or rodents from entering theinterior of such structures, I may provide suitable screening members 8for the outer ends of the passages 6.

It has been found that the grain, or other material, in a state ofrepose has compara tively little tendency to explode, as the dust is notliberated therefrom. It is unnecessary, therefore, after a bin or thelike is filled, to keep the ventilators open. Asa matterof fact, undercertain conditions, open ventilators at such times might beobjectionable, due to the tendency of the moisture to rot the grain. Forovercoming this objection, and supplying moisture vapor only to theworking area above the level of the material being handled, I mayprovide means for automatically stopping the passages 7. Such a means isillustrated in Figures 1 and 2 of the drawings and comprises a disc orpaddle-shaped closure member 9 having a pivotal mounting 10 on an arm 11extending upwardly from the body of the ventilators 5. These closuresare normally maintained in open position to admit moisture to theworking area by suitable counterweights 12 cooperating therewith. Itwill be apparent that the construction is such that as the level ofgrain rises in the bin the pressure of the grain against the closureswill move the same to sealing position as illustrated by the threeventilators below the level of the grain in Figure 1. In'this mannersuch ventilators as are no longer useful may be automatically cut out ofoperation.

It will be understood that changes in the details of construction andthe operation of the invention may be made without departing from thespirit thereof or scope of my broader claims.

A construction such as disclosed herein is particularly adapted for usein constructing new bins or elevators, although its utility is notlimited thereto, and the automatic maintenance of a stabilizedatmospheric condition within the enclosed working area constitutes animportant advantage of the invention.

I claim:

1. In an explosion preventing apparatus, walls enclosing a working areaadapted to receive material producing dust having explosive propertieswhereby a dust laden area is established, an angular ventilator in oneof said walls, and means operated by the material being handled forautomatically closing said ventilator as the material being handledreaches the level thereof,'substantially as described. 7 is 2. In anexplosion preventing apparatus, an enclosing wall, an angularventilator'ex tending through said wall, a screen-like member in saidventilator, and means operated by the material being handled forautomatically closing said ventilator under predetermined conditions,substantially as described.

3. In an explosion preventing apparatus, walls enclosing a working area.adapted to receive material producing dust having ex plosive propertieswhereby a dust laden area is established, a Ventilator extending throughone of said Walls for equalizing atmospheric conditions within andwithout said walls, and means automaticallyclosing said ventilator whenthe level of the material being handled reaches approximately thelevel'of the ventilator, substantially as described In testimony whereofI have hereunto set my hand. i

Rowan T. F. Donne.

